Automated paging device management in a shared memory partition data processing system

ABSTRACT

Automated paging device management is provided for a shared memory partition data processing system. The automated approach includes managing a paging storage pool defined within one or more storage devices for holding logical memory pages external to physical memory managed by a hypervisor of the processing system. The managing includes: responsive to creation of a logical partition within the processing system, automatically defining a logical volume in the paging storage pool for use as a paging device for the new logical partition, the automatically defining occurring absent use of a filesystem, with the resultant paging device being other than a file in a filesystem; and automatically specifying the logical volume as a paging space device for the new logical partition and binding the paging space device to the new logical partition, wherein the logical volume is sized to accommodate a defined maximum memory size of the new logical partition.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional application Ser.No. 61/059,492, filed Jun. 6, 2008, entitled “Virtual Real Memory”, theentirety of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to data processing systems, andmore particularly, to automated paging device management in thehypervisor-managed paging environment of a shared memory partition dataprocessing system.

BACKGROUND OF THE INVENTION

Logical partitions (LPARs) running atop a hypervisor of a dataprocessing system are often used to provide higher-level function thanprovided by the hypervisor itself. For example, one LPAR may bedesignated a virtual input/output server (VIOS), which providesinput/output (I/O) services to one or more other LPARs of the dataprocessing system. This offloading of higher-level function avoidscomplex code in the hypervisor, and thus, assists in maintaining thehypervisor small and secure within the data processing system.

Currently, the number of logical partitions (LPARs) that may be createdon a partitionable server of the data processing system is bound by theamount of real memory available on that server. That is, if the serverhas 32 GBs of real memory, once the partitions have been created andhave been allocated those 32 GBs of real memory, no further logicalpartitions can be activated on that server. This places restriction onthose configurations where a customer may wish to have, for example,hundreds of logical partitions on one partitionable server.

Partitioned computing platforms have led to challenges to fully utilizeavailable resources in the partitioned server. These resources, such asprocessor, memory and I/O, are typically assigned to a given partitionand are therefore unavailable to other partitions on the same platform.Flexibility may be added by allowing the user to dynamically remove andadd resources, however, this requires active user interaction, and cantherefore be cumbersome and inconvenient. Also, memory is difficult tofully utilize in this way since there are frequently large amounts ofinfrequently accessed memory in idle partitions. However, that memoryneeds to be available to the operating system(s) to handle sudden spikesin workload requirements.

SUMMARY OF THE INVENTION

To address this need, the concept of a shared memory partition has beencreated. A shared memory partition's memory is backed by a pool ofphysical memory in the server that is shared by other shared memorypartitions on that server. The amount of physical memory in the pool istypically smaller than the sum of the logical memory assigned to all ofthe shared memory partitions in the pool to allow the memory to be morefully utilized. Idle and/or less active logical memory in the sharedpartitions that does not fit in the physical memory pool is paged out bythe hypervisor to a cheaper and more abundant form of storage (i.e., thepaging devices) via an entity external to the hypervisor known as apaging service partition. In one implementation, the paging device(s)are defined in one or more physical storage disks. Disclosed herein areautomated processes for managing the paging devices, (referred to hereinas the paging space devices), for example, to automatically create,delete and/or resize a paging space device as the corresponding clientlogical partition is created, deleted or resized.

Provided herein therefore, in one aspect, is a computer-implementedmethod of managing paging space devices in a shared memory partitiondata processing system. The method includes: managing a paging storagepool comprising one or more physical storage devices for holding logicalmemory pages external to physical memory managed by a hypervisor of theshared memory partition data processing system. The managing includes:responsive to creation of a new logical partition within the sharedmemory partition data processing system, automatically defining alogical volume for the paging storage pool from block storage for use asa paging space device for the new logical partition, the automaticallydefining occurring absent use of a filesystem, with the paging spacedevice being other than a file in a filesystem, and automaticallyspecifying the logical volume as the paging space device for the newlogical partition and binding the paging space device to the new logicalpartition, wherein the logical volume is sized to accommodate a definedmaximum memory size of the new logical partition.

In another aspect, a shared memory data processing system is provided.The data processing system includes one or more physical storage devicescomprising a paging storage pool for holding logical memory pagesexternal to physical memory managed by a hypervisor of the shared memorypartition data processing system, and a paging service partition coupledto the one or more physical storage devices for managing the pagingstorage pool. The paging service partition is a virtual input/outputserver (VIOS) partition of the shared memory partition data processingsystem, and includes a configuration manager for, in part, managing thepaging storage pool. The configuration manager responds to creation of anew logical partition within the shared memory partition data processingsystem by automatically defining a logical volume in the paging storagepool from block storage for use as a paging space device for the newlogical partition, the automatically defining occurring absent use of afilesystem, with the paging space device being other than a file in afilesystem, and wherein the configuration manager further automaticallyspecifies the logical volume as the paging space device for the newlogical partition and binds the paging space device to the new logicalpartition, wherein the logical volume is sized to accommodate a definedmaximum memory size of the new logical partition.

In a further aspect, an article of manufacture is provided whichincludes at least one computer-readable medium having computer-readableprogram code logic to manage paging space devices in a shared memorydata processing system. The computer-readable program code logic whenexecuting on a processor performing managing of a paging storage poolwithin one or more physical storage devices for holding logical memorypages external to physical memory managed by a hypervisor of the sharedmemory partition data processing system. The managing includes:responsive to creation of a new logical partition within the sharedmemory partition data processing system, automatically defining alogical volume in the paging storage pool for use as a paging spacedevice for the new logical partition. The automatically definingoccurring absent use of a filesystem, wherein the paging device is otherthan a file in a filesystem; and automatically specifying the logicalvolume as the paging space device for the new logical partition andbinding the paging space device to the new logical partition, whereinthe logical volume is sized to accommodate a defined maximum memory sizeof the new logical partition.

Further, additional features and advantages are realized through thetechniques of the present invention. Other embodiments and aspects ofthe invention are described in detail herein and are considered a partof the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention are apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a block diagram of one embodiment of a data processing systemto implement one or more aspects of the present invention;

FIG. 2 is a more detailed illustration of a data processing system whichcould be used to implement one or more aspects of the present invention;

FIG. 3 illustrates one embodiment of a data processing system comprisingmultiple shared memory partitions employing a shared (or common) memorypool within physical memory of the data processing system, in accordancewith an aspect of the present invention;

FIG. 4 illustrates one embodiment of an approach for handling hypervisorpage faults within a shared memory partition data processing system,such as depicted in FIG. 3, in accordance with an aspect of the presentinvention;

FIG. 5 illustrates one embodiment of a paging storage pool (within oneor more or physical storage devices) which is logically configured as aplurality of logical volumes, each logical volume being specified as apaging space device for a respective logical partition of the sharedmemory partition data processing system, in accordance with an aspect ofthe present invention;

FIG. 6 is a flowchart of one embodiment of logic for managing creationof a paging space device for a new logical partition of a shared memorypartition data processing system, in accordance with an aspect of thepresent invention;

FIG. 7 is a flowchart of one embodiment of logic for managing deletionof a logical volume responsive to deletion of a logical partition withina shared memory data processing system, in accordance with an aspect ofthe present invention;

FIG. 8 is a flowchart of one embodiment of logic for managing resizingof a logical volume in the paging storage pool responsive to change inthe corresponding logical partition's maximum memory size, in accordancewith an aspect of the present invention; and

FIG. 9 depicts one embodiment of a computer program productincorporating one or more aspects of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a block diagram of a data processing system 100, which in oneexample, is a symmetric multiprocessing (SMP) server computer system.SMP server computer system 100 includes physical hardware devices thatcan be mapped to, i.e., temporarily owned by, a user application toexecute that application.

SMP server computer system 100 includes a physical SMP server 102.Physical SMP server 102 includes physical hardware devices such asprocessor 104, memory 106, and I/O adapters 108. These physical devicesare managed by hypervisor 110. Processors 104 are shared processors andeach may be a simultaneous multithreading (SMT)-capable processor thatis capable of concurrently executing multiple different threads on theprocessor.

A virtual server is a proxy for a physical server that has the samecapabilities, interfaces, and state. Virtual servers are created andmanaged by a hypervisor that resides on physical SMP server computersystem 100. A virtual server appears to be a physical SMP server to itsuser: the operating system, middleware, and application software thatrun upon it. SMP server computer system 100 includes one or more virtualservers such as virtual server 112 and virtual server 112 a.

Each virtual server appears to its software to include its ownprocessor(s), memory, and I/O adapter(s) that are available for theexclusive use of that virtual server. For example, virtual server 112includes a virtual processor 120, virtual memory 122, and virtual I/Oadapters 124. Virtual server 112 a includes virtual processors 120 a,virtual memory 122 a, and virtual I/O adapters 124 a.

Each virtual server supports its own software environment, including anoperating system, middleware, and applications. The software environmentof each virtual server can be different from the software environment ofother virtual servers. For example, the operating systems executed byeach virtual server may differ from one another.

For example, virtual server 112 supports operating system 114,middleware 116, and applications 118. Virtual server 112 a supportsoperating system 114 a, middleware 116 a, and applications 118 a.Operating systems 114 and 114 a may be the same or different operatingsystems.

A virtual server is a logical description of a server that defines aserver environment that acts, to a user, as if it were a physicalserver, being accessed and providing information in the same way as aphysical server. The virtual processors, virtual memory, and virtual I/Oadapters that are defined for each virtual server are logicalsubstitutes for physical processors, memory, and I/O adapters.

Hypervisor 110 manages the mapping between the virtual servers withtheir virtual processors, virtual memory, and virtual I/O adapters andthe physical hardware devices that are selected to implement thesevirtual devices. For example, when a virtual processor is dispatched, aphysical processor, such as one of physical processors 104, is selectedby hypervisor 110 to be used to execute and implement that virtualprocessor. Hypervisor 110 manages the selections of physical devices andtheir temporary assignment to virtual devices.

Hypervisor 110 services all of the logical partitions during a dispatchtime slice. The dispatch time slice is a particular length of time.During each dispatch time slice, hypervisor 110 will allocate, orassign, the physical processor to each logical partition. When thelogical partition has been allocated time on the physical processor, thevirtual processors defined by that logical partition will be executed bythe physical processor.

Hypervisor 110 is responsible for dynamically creating, managing, anddestroying virtual SMP servers. Whole virtual processors, virtual I/Oadapters, and virtual memory blocks can be removed or added byhypervisor 110. Hypervisor 110 is also responsible for dynamic resourceallocation, managing time-sharing of physical resources, and alteringthe physical resource mapped to a processor without involving theoperating system. Hypervisor 110 is also able to dedicate physicalresources to virtual resources for situations where sharing is notdesired. Hypervisor 110 is responsible for managing the addition orremoval of physical resources. Hypervisor 110 makes these additions anddeletions transparent to the upper level applications.

FIG. 2 is a more detailed illustration of a computer system that may beused to implement the concepts described herein. Data processing system200 may be a symmetric multiprocessor (SMP) system including a pluralityof shared processors or SMT-capable processors, such as processors 202and 204 connected to system bus 206. Alternatively, a single processorsystem may be employed. In the depicted example, processor 204 is aservice processor. Each SMT-capable processor is capable of concurrentlyexecuting multiple hardware threads on the one processor.

Also connected to system bus 206 is memory controller/cache 208, whichprovides an interface to local memory 209. I/O bus bridge 210 isconnected to system bus 206 and provides an interface to I/O bus 212.Memory controller/cache 208 and I/O bus bridge 210 may be integrated asdepicted.

Peripheral component interconnect (PCI) bus bridge 214 connected to I/Obus 212 provides an interface to PCI local bus 216. A number of modemsmay be connected to PCI bus 216. Typical PCI bus implementations willsupport four PCI expansion slots or add-in connectors. Communicationslinks to network computers may be provided through modem 218 and networkadapter 220 connected to PCI local bus 216 through add-in boards.

Network adapter 220 includes a physical layer 282 which conditionsanalog signals to go out to the network, such as for example, anEthernet network for an R45 connector. A media access controller (MAC)280 is included within network adapter 220. Media access controller(MAC) 280 is coupled to bus 216 and processes digital network signals.MAC 280 serves as an interface between bus 216 and physical layer 282.MAC 280 performs a number of functions involved in the transmission andreception of data packets. For example, during the transmission of data,MAC 280 assembles the data to be transmitted into a packet with addressand error detection fields. Conversely, during the reception of apacket, MAC 280 disassembles the packet and performs address checkingand error detection. In addition, MAC 280 typically performsencoding/decoding of digital signals transmitted and performs preamblegeneration/removal as well as bit transmission/reception.

Additional PCI bus bridges 222 and 224 provide interfaces for additionalPCI buses 226 and 228, from which additional modems or network adaptersmay be supported. In this manner, data processing system 200 allowsconnections to multiple network computers. A memory-mapped graphicsadapter 230 and hard disk 232 may also be connected to I/O bus 212 asdepicted, either directly or indirectly.

Service processor 204 interrogates system processors, memory components,and I/O bridges to generate and inventory and topology understanding ofdata processing system 200. Service processor 204 also executesBuilt-In-Self-Tests (BISTs), Basic Assurance Tests (BATs), and memorytests on all elements found by interrogating a system processor, memorycontroller, and I/O bridge. Any error information for failures detectedduring the BISTs, BATs, and memory tests are gathered and reported byservice processor 204.

Those of ordinary skill in the art will appreciate that the hardwaredepicted in FIG. 2 may vary. For example, other peripheral devices, suchas optical disk drives and the like, also may be used in addition to orin place of the hardware depicted. The depicted example is not meant toimply architectural limitations with respect to the present invention.

The present invention may be executed within one of the computers ordata processing systems depicted in FIG. 1 or 2. As a specific,commercially available example, a shared memory partition dataprocessing system implementing hypervisor-managed paging such asdescribed hereinbelow can be built upon technologies found in IBM's p/iSeries product line firmware and systemware, as described in the “PowerArchitecture Platform Reference” (PAPR) material at Power.org(http://www.power.org/members/developers/specs/PAPR_Version_(—)2.7_(—)09Oct07.pdf),which is hereby incorporated herein by reference. In addition, a virtualinput/output server (VIOS) is commercially available as part of aPowerVM computing system offered by International Business MachinesCorporation. The VIOS allows sharing of physical resources betweenlogical partitions, including virtual SCSI and virtual networking. Thisallows more efficient utilization of physical resources through sharingbetween logical partitions and facilitates server consolidation. (IBM,pSeries, iSeries and PowerVM are registered trademarks of InternationalBusiness Machines Corporation, Armonk, N.Y., U.S.A. Other names usedherein may be registered trademarks, trademarks, or product names ofInternational Business Machines Corporation or other companies.)

As noted, partition computing platforms have presented challenges tofully utilize available resources in the partitioned server. Oneapproach to achieving this goal has been the creation of a shared memorypartition data processing system, generally denoted 300, such asdepicted in FIG. 3. As illustrated, the shared memory partition dataprocessing system 300 includes one or more shared memory partitions 310,each of which comprises one or more virtual processors 320, whichinterface through a hypervisor, and more particularly, a hypervisorymemory manager 330, to a shared memory pool 340 within physical memory350 of the shared memory partition data processing system 300. Theamount of physical memory in the pool is typically smaller than the sumof the logical memory assigned to all of the shared memory partitions310 utilizing the shared memory pool to allow the memory to be morefully employed. Idle and/or less active logical memory of one or moreshared memory partitions that does not fit in the shared memory pool 340is paged out by the hypervisor to a more abundant, less expensivestorage (such as disk storage), via a paging service partition 360.Paging service partition 360 is an enhanced virtual input/output service(VIOS) partition configured to facilitate paging-out and paging-in ofmemory pages from or to, respectively, the shared memory pool.

As shown, paging service partition 360 includes a hypervisorconfiguration manager (or configuration manager) 361 and a logicalvolume manager 362. One embodiment of a hypervisor configuration manager361 and a logical volume manager 362 is provided as part of the VIOSpartition provided with the Power5 and Power6 computing platformsoffered by International Business Machines Corporation. Further detailsof a configuration manager for a VIOS partition can be found inhttp://www.redbooks.ibm.com/abstracts/redp4061.html?Open, andhttp://www.redbooks.ibm.com/abstracts/sg247940.html?Open, while furtherdetails of a logical volume manager can be found inhttp://www.redbooks.ibm.com/abstracts/sg245432.html?Open. Generallystated, the hypervisor configuration manager within the VIOS partition,or more particular, to the present invention, within the paging servicepartition, coordinates between the hypervisor and the logical volumemanager to perform various tasks, including the creating, deleting andchanging of logical volume sizes, as described further herein. Thelogical volume manager handles lower-level implementation details,including where to physically place a logical volume on the one or morephysical storage disks and adjusting of the size of a logical volume. Inimplementation, the hypervisor configuration manager employs the logicalvolume manager in implementing the concepts described herein. Providedherein are various enhancements to the configuration manager of thepaging service partition which allows the configuration manager toautomatically manage paging space devices for the logical partitions asthe logical partitions are created, deleted and reconfigured.

Also, although referred to as a shared memory pool, in reality, there isno sharing of memory per se, but rather a sharing of the availability ofa defined amount of physical memory in the pool. This shared memory poolis alternatively characterized as active memory, or virtual real memory.The amount (or volume) of memory within shared memory pool may bedynamically allocated or adjusted between the shared memory partitionsinto sub-volumes or sets of physical pages to accommodate workloads.These dynamically allocated or adjusted sub-volumes or sets of physicalpages from the shared memory pool are associated with the multiplelogical partitions, and may comprise contiguous or disparate physicalmemory locations within the shared memory pool. A physical memory pageof the shared memory pool becomes part of a sub-volume of a particularlogical partition when a logical memory page thereof is associated withor mapped to that physical page. Although referred to as a shared memorypool, there is no concurrent sharing of access to a physical page perse, but rather a sharing of the defined amount of physical memory in thepool. Each shared memory partition with at least one logical memory pagemapped to a physical memory page in the pool has an associatedsub-volume or set of physical memory of the shared memory pool.

The hypervisor utilizes the shared memory pool in combination with thevirtual input/output (VIO) adapter connections to handle pagingoperations for the shared memory partitions. The hypervisor memorymanager manages which physical pages map to which logical memory pagesof a given shared memory partition. The management of these pages istransparent to the shared memory partitions and handled fully by thehypervisor. When a logical page is required by a shared memory partitionand it does not have a physical mapping in the shared memory pool, thehypervisor treats this request to access as an internal fault (i.e.,hypervisor page fault). In response to a hypervisor page fault for alogical memory page that is not resident in the shared memory pool, aninput/output (I/O) paging request is allocated by the hypervisor from apool of free I/O paging requests and sent via the paging servicepartition to the external page storage of the data processing system torequest the needed memory page. The partition's virtual processorencountering the hypervisor page fault is concurrently placed into await state, which blocks further execution of that processor until theI/O paging request is satisfied, or if the hypervisor page faultoccurred while external interrupts were enabled for the virtualprocessor, until an external or timer interrupt occurs. The I/O pagingrequest is submitted to the VIO adapter of the paging service partition,which communicates with the paging service partition in order toretrieve and return the correct logical memory page to fulfill thehypervisor page fault. The same process is also used by the hypervisormemory manager to free up a physical page within the shared memory poolcurrently mapped to a logical memory page of a shared memory partition,for example, when needed by either that shared memory partition oranother shared memory partition.

FIG. 4 illustrates one operational embodiment of handling hypervisorpage faults within a shared memory partition data processing system suchas described above in connection with FIG. 3. In this embodiment, threeshared memory partitions 310, i.e., shared memory partition 1, sharedmemory partition 2 & shared memory partition 3, are illustrated, eachcomprising one or more virtual processors 320, and each encountering ahypervisor page fault 400. Each hypervisor page fault is responsive to arequest by a virtual processor 320 for memory that is not resident inthe shared memory pool 340 of physical memory 350. Responsive to this,the hypervisor memory manager 330 takes an I/O paging request 420 from afree I/O paging request pool 410 and sends, via the paging servicepartition 360, the I/O paging request to the external storage entity 370to request the needed page. Concurrent with requesting the needed page,the partition's virtual processor encountering the hypervisor page faultis placed into a wait state.

As briefly noted above, presented herein is an automated approach tomanaging creation, deletion and resizing of paging space devices forclient logical partitions in a shared memory partition data processingsystem as client logical partitions are created, deleted or resized.Conventionally, hypervisor-level paging employs files in a filesystem aspaging space devices for the data processing system. As one example, aVMware ESX server employs a filesystem to organize paging devices asfiles. When using files in a filesystem, the paging devices may bemanaged by the filesystem to create, delete and resize the correspondingfile. However, paging to a file in a filesystem adds overhead,potentially doubling the CPU resources and physical memory required. Asan alternative approach, a higher performance paging device is providedherein by employing raw block storages, that is, storage of the physicaldisks, as logical volumes, absent use of a filesystem. By eliminatingfilesystem overhead, better performance is achieved, but automaticmanagement of files is no longer conventionally possible, since the userwould need to manage creation of both the logical partition and thepaging space device for use by the logical partition, while ensuringthat the size of the paging space device is equal to or greater than thesize of the memory requirements for the newly created logical partition.Presented hereinbelow is an automated, configuration manager-implementedapproach to managing (in a storage pool lacking a filesystem) pagingdevice creation, deletion and resizing as the corresponding clientlogical partition is created, deleted and resized.

FIG. 5 depicts one embodiment of a physical storage pool designated apaging storage pool. This paging storage pool is within one or morephysical storage devices 370. As illustrated, the paging storage pool isbroken into multiple logical volumes 500, designated volumes V1, V2 &V3, by way of example. (As noted above, logical volumes for differentuses, and the logical volume manager, are known concepts in existingUNIX-based computing systems.) The illustrated logical volumes reside ontop of the underlying physical storage, with each logical volume beingdesignated herein by appropriate metadata as a specific paging device(or paging space device) for a corresponding client logical partition ofthe shared memory partition data processing system. Each logical volumemay comprise a contiguous set of physical memory space (e.g., volumeV3), or a discontinuous set of physical memory space, as illustrated bylogical volume V2 in FIG. 5. In the example illustrated, logical volumeV1 is being extended 501, and logical volume V4 is being created 502.Space 503 remains unused storage space within the paging storage pool.The logical volume manager interfaces with the paging storage pool andhandles reading and writing of memory pages to the defined logicalvolumes. If necessary to resize a logical volume, more space can beadded from the paging storage pool to the logical volume, as explainedfurther below. Also, the logical volumes can be broken into differentpieces of memory such that the memory becomes fragmented within thephysical storage pool.

FIG. 6 depicts one embodiment of configuration manager-implemented logicfor automatically creating a new paging space device for a newly createdlogical partition. As noted, in one embodiment, this logic isimplemented within a configuration manager of a VIOS partition, such asthe hypervisor configuration manager within the paging service partitionillustrated in FIG. 3. The paging storage pool (or volume group) isassumed to hold all of the paging space devices for the client logicalpartitions of the data processing system. Metadata is stored about thelogical volumes to be automatically managed from the paging servicepartition. This allows the data processing system to be able todistinguish between, for example, normal, manual or user-created logicalvolumes and logical volumes designed as paging space devicesautomatically established and managed, as described herein. When a newclient logical partition is created, a new logical volume is allocatedfrom the paging storage pool to be a paging space device for thatlogical partition. Similarly, when the client partition is deleted, itspaging space device is automatically deleted, and when the clientpartition is resized, its paging space device is automatically resizedto match. This automated management facility allows a storage pool to beused that is not dedicated to containing only automatically establishedpaging devices. For example, the storage pool could containmanually-created logical volumes that may or may not be used as pagingdevices, without disrupting the user's manual configuration or thenon-paging devices within the storage pool. Also, by allowing storage tobe managed by the hypervisor configuration manager, non-paging storagein the volume group can be protected by not requiring the user to haveaccess to the storage pool configuration. Therefore, accidental deletionof real data can be eliminated.

As shown in FIG. 6, when a client logical partition is created 600, anew logical volume is to be allocated from the paging storage pool. Thisnew logical volume is to have a size equal to the logical memoryallocation for the client logical partition, and thus, the new maximummemory size for the new logical partition is obtained 610. Metadata isused to designate by the configuration manager that this logical volumeis being created automatically for the purposes of being a paging spacedevice.

The manager verifies that there is an existing paging storage pool,which allows for the automated selection of logical volumes 620. As adefault, a paging storage pool may be created with initialization of thesystem. Assuming that at least one paging storage pool as describedherein exists, then the configuration manager automatically creates alogical volume in the paging storage pool for the newly created clientlogical partition 630. This logical volume is then added or designatedas a paging space device for the newly created client logical partition640, and the paging space device is bound or mapped to the logicalpartition 650, which completes automated creation of the paging spacedevice for the newly created logical partition 665. If there is noexisting paging storage pool for automated logical volume designation,then the configuration manager selects a manually-created (for example,by a system administrator) paging space device 660 from the storagepool, and binds this manually-created paging space device to the newlycreated logical partition 650, which completes processing 665.

As illustrated in FIG. 7, the configuration manager is also providedwith logic to automatically respond to deletion of a client logicalpartition 700 by determining whether the corresponding paging spacedevice for that logical partition includes metadata which indicates thatit was automatically created to be a paging space device. If “yes”, thenthe logical volume is automatically deleted by first removing binding ormapping of the paging space device to the logical volume being deleted720, and then deconfiguring the logical volume from being a paging spacedevice 730, after which the logical volume is deleted 740, whichcompletes processing 745. Note that deletion of the logical volume freesthe space in the storage pool for use by, for example, another clientlogical partition. If the corresponding paging space device was notautomatically created, then the configuration manager removes binding ofthe paging space device to the logical volume 750, which completesprocessing 745. In this case, the paging space device remains within thestorage pool but is unbound or unmapped to a particular logical volume.Note that by automatically deleting logical volumes as described herein,the customer does not have to track the storage pool configuration, aswell as their logical partition configuration, since the configurationmanager automatically maintains both configurations in sync.

FIG. 8 illustrates one embodiment of configuration manager logic forchanging size of a logical volume responsive to resizing of thecorresponding logical partition. When a client logical partition'smemory allocation changes 800, the configuration manager obtains a newmaximum memory size for the resized logical partition 810. The managerthen determines whether the partition's paging space device is a logicalvolume that has metadata which indicates that it was automaticallycreated to be a paging space device for that logical partition 820, andif so, the manager automatically resizes the logical volume for theresized logical partition 830, which completes processing 835. If themetadata does not indicate that the associated paging space device wasautomatically created for the logical partition being resized, thenbinding of the paging space device to the resized logical partition isremoved 840, and an existing, manually-created paging space device inthe storage pool is selected 850. This new paging space device is thenbound or mapped to the resized logical partition 860, which completesthe reconfiguration processing 835. Note that by having theconfiguration manager know which logical volumes can be automatically bemanaged, enhanced performance is gained by having the system be able touse space within the paging storage pool without having to clear it,since it is used for paging, any reads of a “sector” that has not beenwritten can be rejected. This allows for faster defragmentation of thepaging space device when client partitions are powered off.

Optimizing defragmenting of the storage pool is facilitated herein bythe configuration manager concepts described above. By optimizingdefragmentation, enhanced performance of the storage pool is obtained.For example, if the following logical volumes are fragmented:

Defragmenting of the storage pool can result in:

The defragmentation operation is optimized because the configurationmanager knows which subset of logical volumes is currently in use andneed only copy those portions. This can be accomplished by interpretinga bitmap at the beginning of a logical volume which determines whichportions have valid data. This bitmap is not built into the logicalvolume manager, but could be part of the application logic for thepaging space device management (i.e., data within the logical volume).

Further details on shared memory partition data processing systems areprovided in the following, co-filed patent applications, the entirety ofeach of which is hereby incorporated herein by reference:“Hypervisor-Based Facility for Communicating Between a HardwareManagement Console and a Logical Partition”, U.S. Ser. No. 12/403,402;“Hypervisor Page Fault Processing in a Shared Memory Partition DataProcessing System”, U.S. Ser. No. 12/403,408; “Managing Assignment ofPartition Services to Virtual Input/Output Adapters”, U.S. Ser. No.12/403,416; “Dynamic Control of Partition Memory Affinity in a SharedMemory Partition Data Processing System”, U.S. Ser. No. 12/403,440;“Transparent Hypervisor Pinning of Critical Memory Areas in a SharedMemory Partition Data Processing System”, U.S. Ser. No. 12/403,447;“Shared Memory Partition Data Processing System with Hypervisor ManagedPaging”, U.S. Ser. No. 12/403,459; “Controlled Shut-Down of PartitionsWithin a Shared Memory Partition Data Processing System”, U.S. Ser. No.12/403,472; and “Managing Migration of a Shared Memory Logical PartitionFrom a Source System to a Target System”, U.S. Ser. No. 12/403,485.

One or more aspects of the present invention can be included in anarticle of manufacture (e.g., one or more computer program products)having, for instance, computer usable media. The media has therein, forinstance, computer readable program code means or logic (e.g.,instructions, code, commands, etc.) to provide and facilitate thecapabilities of the present invention. The article of manufacture can beincluded as a part of a computer system or sold separately.

One example of an article of manufacture or a computer program productincorporating one or more aspects of the present invention is describedwith reference to FIG. 9. A computer program product 900 includes, forinstance, one or more computer-readable media 910 to store computerreadable program code means or logic 920 thereon to provide andfacilitate one or more aspects of the present invention. The medium canbe an electronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system (or apparatus or device) or a propagation medium.Examples of a computer readable medium include a semiconductor or solidstate memory, magnetic tape, a removable computer diskette, a randomaccess memory (RAM), a read-only memory (ROM), a rigid magnetic disk andan optical disk. Examples of optical disks include compact disk-readonly memory (CD-ROM), compact disk-read/write (CD-R/W) and DVD.

A sequence of program instructions or a logical assembly of one or moreinterrelated modules defined by one or more computer readable programcode means or logic direct the performance of one or more aspects of thepresent invention.

Although various embodiments are described above, these are onlyexamples.

Moreover, an environment may include an emulator (e.g., software orother emulation mechanisms), in which a particular architecture orsubset thereof is emulated. In such an environment, one or moreemulation functions of the emulator can implement one or more aspects ofthe present invention, even though a computer executing the emulator mayhave a different architecture than the capabilities being emulated. Asone example, in emulation mode, the specific instruction or operationbeing emulated is decoded, and an appropriate emulation function isbuilt to implement the individual instruction or operation.

In an emulation environment, a host computer includes, for instance, amemory to store instructions and data; an instruction fetch unit tofetch instructions from memory and to optionally, provide localbuffering for the fetched instruction; an instruction decode unit toreceive the instruction fetch unit and to determine the type ofinstructions that have been fetched; and an instruction execution unitto execute the instructions. Execution may include loading data into aregister for memory; storing data back to memory from a register; orperforming some type of arithmetic or logical operation, as determinedby the decode unit. In one example, each unit is implemented insoftware. For instance, the operations being performed by the units areimplemented as one or more subroutines within emulator software.

Further, a data processing system suitable for storing and/or executingprogram code is usable that includes at least one processor coupleddirectly or indirectly to memory elements through a system bus. Thememory elements include, for instance, local memory employed duringactual execution of the program code, bulk storage, and cache memorywhich provide temporary storage of at least some program code in orderto reduce the number of times code must be retrieved from bulk storageduring execution.

Input/Output or I/O devices (including, but not limited to, keyboards,displays, pointing devices, DASD, tape, CDs, DVDs, thumb drives andother memory media, etc.) can be coupled to the system either directlyor through intervening I/O controllers. Network adapters may also becoupled to the system to enable the data processing system to becomecoupled to other data processing systems or remote printers or storagedevices through intervening private or public networks. Modems, cablemodems, and Ethernet cards are just a few of the available types ofnetwork adapters.

The capabilities of one or more aspects of the present invention can beimplemented in software, firmware, hardware, or some combinationthereof. At least one program storage device readable by a machineembodying at least one program of instructions executable by the machineto perform the capabilities of the present invention can be provided.

The flow diagrams depicted herein are just examples. There may be manyvariations to these diagrams or the steps (or operations) describedtherein without departing from the spirit of the invention. Forinstance, the steps may be performed in a differing order, or steps maybe added, deleted, or modified. All of these variations are considered apart of the claimed invention.

Although embodiments have been depicted and described in detail herein,it will be apparent to those skilled in the relevant art that variousmodifications, additions, substitutions and the like can be made withoutdeparting from the spirit of the invention and these are thereforeconsidered to be within the scope of the invention as defined in thefollowing claims.

What is claimed is:
 1. A computer-implemented method of managing apaging space device in a shared memory partition data processing system,the method comprising: managing a paging storage pool comprising one ormore physical storage devices for holding logical memory pages externalto physical memory managed by a hypervisor of the shared memorypartition data processing system, the managing comprising: responsive tocreation of a new logical partition within the shared memory partitiondata processing system, automatically defining a logical volume in thepaging storage pool from block storage for use as said paging spacedevice for the new logical partition, the automatically definingoccurring absent use of a filesystem, wherein the said paging spacedevice is other than a file in a filesystem; and automaticallyspecifying the logical volume as the paging space device for the newlogical partition and binding the paging space device to the new logicalpartition, wherein the logical volume is sized to accommodate a definedmaximum memory size of the new logical partition.
 2. The method of claim1, wherein the managing is performed by a configuration manager within apaging service partition of the shared memory partition data processingsystem, the paging service partition interfacing the hypervisor and thepaging storage pool of the shared memory partition data processingsystem.
 3. The method of claim 1, wherein the managing furthercomprises, responsive to creation of the new logical partition withinthe shared memory partition data processing system, automaticallyobtaining the defined maximum memory size of the new logical partition,and verifying existence of the paging storage pool comprising the one ormore physical storage devices, and if so, proceeding with theautomatically defining, and the automatically specifying and binding. 4.The method of claim 3, wherein the one or more physical storage devicesinclude automatically defined logical volumes specified as paging spacedevices by the managing, as well as manually-created, user-definedpaging space devices.
 5. The method of claim 1, wherein the managingfurther comprises: responsive to deletion of a logical partition of theshared memory partition data processing system, determining whether apaging space device of the logical partition being deleted wasautomatically established by the managing, and if so, removing bindingof that paging space device to its corresponding logical volume,deconfiguring that logical volume from being a paging space device, anddeleting that logical volume, thereby returning that logical volume tounused storage within in the paging storage pool.
 6. The method of claim5, wherein the managing further comprises removing binding of the pagingspace device of the logical partition being deleted to the deletedlogical volume when the paging space device of the logical partitionbeing deleted was other than automatically established by the managing,thereby freeing the paging space device of the logical partition beingdeleted for subsequent use.
 7. The method of claim 1, wherein themanaging further comprises, responsive to change in a defined maximummemory size of a logical partition, obtaining a new maximum memory sizeof a resized logical partition, and determining whether its paging spacedevice in the paging storage pool was automatically established by themanaging, and if so, automatically resizing the logical volume for theresized logical partition within the paging storage pool to correspondwith a change in the defined maximum memory size of the resized logicalpartition.
 8. The method of claim 7, wherein the managing furthercomprises, when the resized logical partition's paging space device inthe paging storage pool was other than automatically established by themanaging, removing binding of that paging space device to the resizedlogical partition, selecting a different, manually-created paging spacedevice for the resized logical partition, and binding the selectedpaging space device to the resized logical partition.
 9. A shared memorypartition data processing system comprising: one or more physicalstorage devices comprising a paging storage pool for holding logicalmemory pages external to physical memory managed by a hypervisor of theshared memory partition data processing system; a paging servicepartition coupled to the one or more physical storage devices formanaging the paging storage pool, the paging service partition being avirtual input/output server (VIOS) partition of the shared memorypartition data processing system, and the paging service partitioncomprising a configuration manager for, in part, managing the pagingstorage pool; and wherein the configuration manager responds to creationof a new logical partition within the shared memory partition dataprocessing system by automatically defining a logical volume in thepaging storage pool from block storage for use as a paging space devicefor the new logical partition, the automatically defining occurringabsent use of a filesystem, wherein the paging space device is otherthan a file in a filesystem, and wherein the configuration managerautomatically specifies the logical volume as the paging space devicefor the new logical partition and binds the paging space device to thenew logical partition, wherein the logical volume is sized toaccommodate a defined maximum memory size of the new logical partition.10. The shared memory partition data processing system of claim 9,wherein the configuration manager responds to deletion of a logicalpartition of the shared memory partition data processing system bydetermining whether the deleted logical partition's paging space devicewas automatically established by the configuration manager, and if so,by removing binding of the paging space device of the deleted logicalpartition to the deleted logical partition, deconfiguring acorresponding logical volume from being a paging device, and deletingthe corresponding logical volume, thereby returning the correspondinglogical volume to unused storage within the paging storage pool.
 11. Theshared memory data processing system of claim 10, wherein theconfiguration manager further responds to deletion of a logicalpartition of the shared memory partition data processing system byremoving binding of its paging space device to the deleted logicalvolume when the paging space device of the deleted logical partition wasother than automatically established by the configuration manager,thereby freeing the paging space device of the deleted logical partitionfor subsequent use.
 12. The shared memory data processing system ofclaim 9, wherein the configuration manager responds to a change in adefined maximum memory size of a resized logical partition in the sharedmemory partition data processing system by obtaining a new maximummemory size of the resized logical partition, and determining whetherits paging space device was automatically established by theconfiguration manager, and if so, by automatically resizing a logicalvolume for the resized logical partition within the paging storage poolto correspond to the change in the defined maximum memory size of theresized logical partition.
 13. The shared memory data processing systemof claim 12, wherein the configuration manager, when the resized logicalpartition's paging space device in the paging storage pool was otherthan automatically established by the configuration manager, responds tothe change in the defined maximum memory size of the resized logicalpartition by removing binding of the paging space device of the resizedlogical partition, selecting a different, manually-created paging spacedevice for the resized logical partition, and binding the selectedpaging space device to the resized logical partition.
 14. An article ofmanufacture comprising: at least one non-transitory computer-readablemedium having computer-readable program code logic to manage a pagingspace device in a shared memory partition data processing system, thecomputer-readable program code logic when executing on a processorperforming: managing a paging storage pool within one or more physicalstorage devices for holding logical memory pages external to physicalmemory managed by a hypervisor of the shared memory partition dataprocessing system, the managing comprising: responsive to creation of anew logical partition within the shared memory partition data processingsystem, automatically defining a logical volume in the paging storagepool from block storage for use as said paging space device for the newlogical partition, the automatically defining occurring absent use of afilesystem, wherein the said paging space device is other than a file ina filesystem; and automatically specifying the logical volume as thesaid paging space device for the new logical partition and binding thesaid paging space device to the new logical partition, wherein thelogical volume is sized to accommodate a defined maximum memory size ofthe new logical partition.
 15. The article of manufacture of claim 14,wherein the managing is performed by a configuration manager within apaging service partition of the shared memory partition data processingsystem, the paging service partition interfacing the hypervisor and thepaging storage pool of the shared memory partition data processingsystem.
 16. The article of manufacture of claim 14, wherein the managingfurther comprises, responsive to creation of the new logical partitionwithin the shared memory partition data processing system, automaticallyobtaining the defined maximum memory size of the new logical partition,and verifying existence of the paging storage pool within the one ormore physical storage devices, and if so, proceeding with theautomatically defining, and the automatically specifying and binding.17. The article of manufacture of claim 14, wherein the managing furthercomprises: responsive to deletion of a logical partition of the sharedmemory partition data processing system, determining whether a pagingspace device of the logical partition being deleted was automaticallyestablished by the managing, and if so, removing binding of that pagingspace device to its corresponding logical volume, deconfiguring thatlogical volume from being a paging space device, and deleting thecorresponding logical volume, thereby returning the logical volume tounused storage within in the paging storage pool.
 18. The article ofmanufacture of claim 17, wherein the managing further comprises removingbinding of the paging space device of the logical partition beingdeleted to the deleted logical volume when the paging space device ofthe logical partition being deleted was other than automaticallyestablished by the managing, thereby freeing the paging space device ofthe logical partition being deleted for subsequent use.
 19. The articleof manufacture of claim 14, wherein the managing further comprises,responsive to change in a defined maximum memory size of a logicalpartition, obtaining a new maximum memory size of a resized logicalpartition, and determining whether its paging space device in the pagingstorage pool was automatically established by the managing, and if so,automatically resizing a logical volume for the resized logicalpartition within the paging storage pool to correspond with the changein the defined maximum memory size of the said logical partition. 20.The article of manufacture of claim 19, wherein the managing furthercomprises, when the resized logical partition's paging space device inthe paging storage pool was other than automatically established by themanaging, removing binding of the paging space device of the resizedlogical partition to the resized logical partition, selecting adifferent, manually-created paging space device for the resized logicalpartition, and binding the selected paging space device to the resizedlogical partition.